AES E-Library

With the continuing growth of multichannel audio formats, the issue of downmixing to legacy formats such as stereo or mono remains an important problem. Traditional downmix methods use fixed downmix coefficients and mixing equations to blindly combine N input channels into M output channels, where N is greater than M. This commonly produces unpredictable and unsatisfactory results due to the dependence of these passive methods on input signal characteristics. In this paper, an active downmix enhancement employing frequency domain analysis of key inter-channel spatial cues is described which minimizes various distortions commonly observed in passively downmixed audio such as spatial inaccuracy, timbre change, signal coloration, and reduced intelligibility.